Intracarotid infusions of noradrenaline (0.3 nmol.kg(-1) x min(-1)) stimulated salivary fluid secretion and caused increases in salivary concentrations of protein, potassium. magnesium. chloride and phosphate, and decreases in bicarbonate. These effects of intracarotid noradrenaline were not reduced by simultaneous intracarotid infusion of phentolamine (3.0 nmol.kg(-1) x min(-1)) but were significantly greater than the responses accompanying intravenous noradrenaline infusion. Concomitant administration of the beta-antagonist, CGP20712A, were much more effective in blocking the noradrenaline-induced changes in salivary composition than equimolar infusions of the beta2-antagonist, ICI118551, thereby confirming the presence of beta1-adrenoreceptors. Intracarotid infusion of salbutamol at 0.6 nmol x kg(-1) x min(-1) and 6.0 nmol x kg(-1) x min(-1) caused increasing but qualitatively similar changes in salivary composition to intracarotid noradrenaline but was less effective than noradrenaline in augmenting salivary protein release. Equimolar intravenous infusions of salbutamol and noradrenaline were equally potent in altering salivary electrolyte concentrations but salbutamol by this route had less effect on protein release and fluid secretion. Concurrent intravenous and intracarotid infusions of beta1-(CGP) and beta2-(ICI) antagonists with intracarotid salbutamol showed that the beta2-antagonist was more potent than the beta1-antagonist by the intracarotid route thereby demonstrating the presence of glandular beta2-receptors and eliminating the possibility that the response to salbutamol was due totally by reflex increases in general sympathetic tone triggered by lowered blood pressure. It was concluded that the kangaroo parotid has functional beta1- and beta2-adrenoreceptor subtypes in endpieces whereas the data provide little support for either adrenoreceptor subtype being present in the excurrent duct system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.